Certain 2-benzimidazole carbamates used as fungicides

ABSTRACT

THIS APPLICATION IS DIRECTED TO A METHOD OF USING COMPOUNDS CORRESPONDING TO THE FORMULA   1-(R1-CO-),2-(CH3-OOC-N=),3-(R2-CO-)BENZIMIDAZOLINE   WHEREIN R1 AND R2 CAN BE THE SAME OR DIFFERENT AND ARE SELECTED FROM ALKYL, ARYL HALOALKYL, CYCLOALKYL, ALLENYLARYL, AND FURANYL. THE COMPOSITIONS DESCRIBED HEREIN ARE USEFUL AS FUNGICIDES.

United States Patent 3,803,317 CERTAIN Z-BENZIMIDAZOLE CARBAMATES USED AS FUNGICIDES Don R. Baker, Orinda, Calif., assignor to Staufier Chemical Company, New York, N.Y.

No Drawing. Original application Sept. 25, 1970, Ser. No. 75,753, now Patent No. 3,692,783. Divided and this application May 18, 1972, Ser. No. 254,597

Int. Cl. A01n 9/22 US. Cl. 424-273 3 Claims ABSTRACT OF THE DISCLOSURE This application is directed to a method of using com pounds corresponding to the formula This application is a division of application Ser. No. 75,753, filed Sept. 25, 1970, now US. Pat. No. 3,692,783.

Description of the invention The present invention is concerned with a novel group of compounds which can be generally described as 2-benzimidazole carbamates, and their use as pesticides, especially effective against fungi.

The compounds are represented by the general formula wherein R and R can be the same or different and can be selected from alkyl, aryl, haloalkyl, cycloalkyl, al'kenylaryl, and furanyl.

The compounds represented by the above general formula are manufactured by reacting a 2-benzimidazole alkyl carbamate in an inert solvent with an acid chloride or other like material in the presence of an acid acceptor. The inert solvent can be selected from benzene, chloroform, or the like. The acid acceptor can be selected from triethylamine, pyridine, or the like. In order to illustrate the merits of the present invention, the following examples are provided.

EXAMPLE I Preparation of o b -om-orr, .'q

A mixture of 9.6 grams (0.05 mole) of 2-benzimidazole methyl carbamate, ml. of chloroform and 10.5 ml. (0.12 mole) of propionyl chloride was prepared. Then, 16.8 ml. of triethylamine in 30 ml. of chloroform was added to the mixture with stirring over a period of 1 hour and forty minutes at 22-26 C. The mixture was stirred for 30 minutes and then washed with 100 m1. of

water, dried over MgSO and evaporated in vacuo to yield an oil that crystallized from ethyl ether to yield 10.2 grams of solid with M.P. of 103-105 C.

EXAMPLE 11 Preparation of A mixture of 9.6 grams (0.05 mole) of 2-benzimidazole methyl carbamate, 100 ml. of chloroform and 12.5 grams cyclopropane carboxylic acid chloride was formed. Then, 17 ml. of triethylamine was added dropwise with stirring over a period of 30 minutes at 18-20" C. and the mixture stirred at room temperature for 18 hours. The solution was washed with 100 ml. water, dried over MgSO and evaporated in vacuo to yield an oil that crystallized from cold ethyl ether to yield 13 grams of crystals after air drying. M.P. 108-109 C.

EXAMPLE III Other compounds were prepared in an analogous manner starting with the appropriate starting materials, as outlined above. The following is a table of compounds representative of those embodied by the present invention. Compound numbers have been assigned to them and are used for identification throughout the balance of the specification.

TABLE 1 0 t- N 1 1IJ)=N-i-OCH:

Compound R1 R2 number I '3 l l l l 2 Q Q 3 n 4 C2115 C2H5 5 OHzCHnCl CHzCHzCl 6 /CH:| CH1 C H\ C4 7 CH3 CH3 3 FUNGICIDE TESTING rnocnnunns A. Foliar preventative sprays 1. Bean rust.The chemicals are dissolved in an appropriate solvent and diluted with water containing several drops of T ween-20, a wetting agent. Test concentrations, ranging from 1000 p.p.m. downward, are sprayed to runoif on the primary leaves of pinto beans (Phaseolus vulgaris L.). After the leaves are dried, they are inoculated with a water suspension of spores of the bean rust fungus (Uromyces phaseoli Arthur) and the plants are placed in an environment of 100% humidity for 24 hours. The plants are then removed from the humidity chamber and held until disease pustules appear on the leaves. Effectiveness is recorded as percent reduction in number of pustules as compared to untreated inoculated plants.

2. Bean powdery mildew.Test chemicals are prepared and applied in the same manner as for the bean rust test. After the plants are dry, the leaves are dusted with spores of the powdery mildew fungus (Erysz'phe polygom' De Candolle) and the plants are retained in the greenhouse until the fungal growth appears on the leaf surfaces. Effectiveness is recorded as percent of the leaf tration, in p.p.m., which will provide a 50% reduction in mycelial growth on the leaf surface as compared to untreated, inoculated plants.

BIOCIDE TESTING PROCEDURES Tubes of sterilized nutrient and malt extract broth are prepared. Aliquots of the toxicant, dissolved in an appropriate solvent, are injected through the stopper, into the broth, to provide concentrations ranging from 50 p.p.m. downward. The test organisms consist of two fungi, Aspergillus niger (A.n.) van Tieghem and Penicillium italicum (P.i) Wehmer, and two bacteria, Escherichia coli (\EJL) Migula and Staphylococcus aureus (S.a) Rosenbach. Three drops of a spore suspension of each of the fungi are injected into the tubes of malt broth and three drops of the bacteria are injected into the nutrient broth. One week later the growth of each organism is observed and effectiveness of the chemical is recorded as the lowest concentration in p.p.m. which provides 50% inhibition of growth as compared to untreated inoculated tubes.

The results of the above tests are set forth in the following table.

TABLE II Preventative sprays (p.p.m.)

Tube systemic In vitro vial (p.p.m.) Rust Mildew (p.p.m.)

Compound number Am. Pi. Em. S.a. 1,000 500 100 1,000 500 100 50 10 Bust Mildew surface free of fungal growth as compared to untreated inoculated plants.

'B. Tube systemic test 1. Bean rust.-The chemicals are dissolved in an appropriate solvent and diluted with tap water to a series of descending concentrations beginning at 50 p.p.m. Sixty ml. of each concentration are placed in a test tube. A pinto bean plant is placed in each tube and supported with a piece of cotton so that only the roots and lower stem are in contact with the test solution. Forty-eight hours later the bean leaves are inoculated with a water suspension of spores of the bean rust fungus and placed in an environment with humidity for 24 hours. The plants are then removed from the humidity chamber and maintained in the greenhouse until the disease pustules appear on the leaves. Effectiveness is recorded as the lowest concentration, in p.p.m., which will provide 50% reduction in pustule formation as compared to untreated, inoculated plants.

2. Bean powdery mildew.-Test chemicals are prepared and applied in the same manner as for the bean rust systemic test. After two days the leaves are dusted with spores of the powdery mildew fungus and maintained in the greenhouse until mycelial growth appears on the leaf surfaces. Effectiveness is recorded as the lowest concen- What is claimed is: 1. A method of controlling fungi comprising applying to the habitat thereof a fungicidally effective amount of 0 a compound having the formula 3. The method of claim 1 wherein R and R are styryl.

References Cited UNITED STATES PATENTS 3,541,213 11/1970 Klopping 424-273 3,692,783 9/1972 Baker 260-240 U ALBERT T. MEYERS, Primary Examiner L. SCHENKMAN, Assistant Examiner as UNITED STATES PATENT OFFICE CERTEFICATE OF CORRECTION Patent No. 3,803,317 Dated April 9, 1974 Inventor(s) Dori R. Baker It is certified that error appears in the abovc-identiifiad patent and that said Letters Patent are hereby corrected as shown below:

a"- v m in Column l the title CERTQEEI Z-BENZIMIDAZOLE CARBAFATES AND THEl'R mumsin Column l, line 36 the portion reading "This application is" should read -----This 18-.

In Column 2 line 1,, the word "mole should read ---moles--- In Column 2, line 3, the word "mole" should read ---moles---. In Column 2, line 24, the word "mole" should read ---moles--. In Column line 49, the portion of the line reading "selected from the group consisting of" should read ---selected fm m---.

In Column '4, in the 1st Claim, in the formula, the formula should read g- L j-ocn O:I 2 Signed and sealed this 22nd day of October 1974.

(SEAL) Attest:

MCCOY M. GIBSON JR. I C. MARSHALL DANN Attesting Officer Commissioner of Patents 

